New to DSM and cars running rough

[dstix06]

Hi guys,
Im new to the DSM scene and I bought a 98 GSX and it seemed to run fine til I got it home (go figure)
It now has a rough idle that seems to surge slightly. it was vented to atmosphere so I re circulated it. I put in new plugs and wires. None of this seemed to help much. When I rev it or push the clutch in while driving the RPMs will drop right down and it will stall or almost stall. I used starting fluid to check for vaccumm leaks and found nothing. all hose clamps are tight on intake (injen) and all intercooler/turbo hoses. When I unplug the MAF it surges worse leading me to believe its working but maybe not 100%?? Can it be bad but still work partially? Please help I spent alot on this car and want it running right. thanks

 

[talonawd1991]

Try Boost leak testing it. All spark plug wires are snug and plugs are gapped corecty. Also is anything aftermarket on it? such as dsmlink or injectors? If your battery died you might have lost the tune on link if you have it.

 

[dstix06]

No DSM LINK and everything is stock besides an Injen intake and SQ blowoff valve. Battery did die a few times in the past but I fixed the drain. I checked all clamps on turbo hoses and everything seems tight. is there a way to test for a boost leak if I dont have a compressor and attachment for the turbo? I took the intake off today and turbo is spinning freely but fin does have some play in it. Is that shaft play??

Also did plugs today. Gapped to .32 and they are NGK bpr6es. Wires are tight and I tried 2 sets

 

[talonawd1991]

Some play is fine as long as its not a crazy amount.
You can make a boost leak tester at your local ace or home depot for cheap and not having much boost over stock id just use a bicycle pump. A compressor is needed for guys Boost leak testing to like 50+ lbs.

But a compressor is a good tool to have none the less

 

[ChunkyLover53]

Sometimes problems with the ISC can cause idle surge and other issues with idle. Check out the link below and it shows some videos on how to test the ISC. It's a good place to start along with a boost leak test.

The video shows the location and how to test an ISC pretty well.

http://www.dsmtuners.com/forums/newbie-forum/385795-bad-isc-motor.html

 

[dstix06]

Yeah I saw a video on youtube. So just cover all connections with soapy water and push air through? I tried it today in a few spots by reving the engine and spraying hoses but did not know if that would work??

 

[92AWDHX40]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

this may help too with your idle surge problems, nice list to test, and rule things out.

 

[ChunkyLover53]

Yeah I saw a video on youtube. So just cover all connections with soapy water and push air through? I tried it today in a few spots by reving the engine and spraying hoses but did not know if that would work??

It probably will not work with the engine on because it will be sucking in the water not blowing out. The idea is to pressurize the system without the engine running so that if there is a leak somewhere you will hear air escaping and possibly see exactly where it is if it is blowing the water you sprayed on it.

 

[dstix06]

I will try to build a tool to test it. Thanks and I will check out the links to rule out other problems. Want the car running good by spring

After reading the links I will check the isc. sounds like an easy test and its causing the same symptoms Im having. Thanks

 

[Lou98GSX]

don't think the engine is pulling enough air at idle . you could have a dirty throttle body or the air bypass adjustment is off . try turning the bypass screw on top of throttle body a half a turn counter clockwise to see if it runs better . the screw might have a black rubber plug blocking it . its a large fillip screw in the upper front .

 

[dstix06]

Is that the "idle screw" on the front of the throttle body? I did adjust that. RPMs come up but then it goes into a fit again and wants to almost stall at idle. Does stall while driving and coming to a stop. It is running very lean with almost no voltage registering on the o2s. Plugs are burning real hot too. Fuel pressure was checked and I was told it was ok??

 

[dstix06]

So I pulled my isc today. All coils test out fine. When I cycled the key on and off the motor moved in and out as it should. Little twitch at first? Also it is one of the tan motors that I read were replaced with black due to issues. Not sure it's my problem though

 

[keltalon]

So I pulled my isc today. All coils test out fine. When I cycled the key on and off the motor moved in and out as it should. Little twitch at first? Also it is one of the tan motors that I read were replaced with black due to issues. Not sure it's my problem though

check to make sure that the TPS sensor have not vibrated loose and do this with all your sensors cam, Isc ect. Also check for broken or loose wires I know this is time consuming but it rules out a lot and you will be surprised as to the other things you will end up fixing as you check.

 

[dstix06]

The tps was a little loose so I tightened it up. Idle got better but Still not right though. Im having a new downpipe put on because I have an exhaust leak in my flex pipe so hoping that helps a little too. Is there a way to test the EGR valve and MAF sensor to rule those out as well without buying replacements? thanks

Oh and i did clean some crap out of the intake manifold too. Alot of black buildup in there

 

[keltalon]

The tps was a little loose so I tightened it up. Idle got better but Still not right though. Im having a new downpipe put on because I have an exhaust leak in my flex pipe so hoping that helps a little too. Is there a way to test the EGR valve and MAF sensor to rule those out as well without buying replacements? thanks

Oh and i did clean some crap out of the intake manifold too. Alot of black buildup in there

Another thing you might want to check is the connection to the mas. Sometimes it get a little corroded and some of the most important pins will not make proper contact this will also cause the car to run rough. Keep up posted

 

[dstix06]

Got my car back today with a new downpipe and cat. Does not seem to be stalling anymore and the idle is a little better since cleaning the tb. I did however get a p0170 fuel trim bank 1 cel code after taking a short drive. Figure I'll check out the maf and connections on my day off this week. Maybe the o2 as well?? I bought cleaner but then realized i have a karmen vortex system and can't use it

 

[92AWDHX40]

Again read the idle post, i posted for you, seems like your almost there. Any cels? A bad o2 will throw a code, narrow one thing down at a time, you may find one problem may solve your issue or several ones combined.

 

[dstix06]

I have been checking all the sensors. Only CEL code I got was fuel trim bank 1. Today was the 1st day I was able to actually drive the car to work (50 mile round trip) amd the CEL came back on for the same code. It seemed to be running decent today,It only stalled on me once but did not seem like it was getting all the power it should (acceleration wise top end). Also running 10 mph faster on speedo then actual speed?? seperate issue?? When I got home I took of the MAF off to look at it. Wires seemed ok and maf looked fine. I wiped it out a little and cleaned the connector with electric contact spray. Put it back together and now it bogs and pops. Does not like low RPMs. Messed with the TPS a little but did not help. Think I F'd the MAF up??? Getting a used one tomorrow with a K&N Filter on it fot $60. Hope it helps. thought I had it

 

[dstix06]

Put the New to me MAF on today and it made a noticable difference. Car drives nice now and has good pickup. I can even hear my recirculated BOV now with the open cone filter. Idle still not perfect but much better. Still trying to get the Biss and TPS set correctly. I also still get the fuel trim bank 1 code?? Maybe a bad o2?? Thanks for everyones help and opinions.

 

[keltalon]

Put the New to me MAF on today and it made a noticable difference. Car drives nice now and has good pickup. I can even hear my recirculated BOV now with the open cone filter. Idle still not perfect but much better. Still trying to get the Biss and TPS set correctly. I also still get the fuel trim bank 1 code?? Maybe a bad o2?? Thanks for everyones help and opinions.

Yeah bank 1 is definitely your 02 sensor.

 

[dstix06]

I discovered my throttle body is leaking when I performed a boost test. I want to get a replacement. Did they use the same throttle body in the non turbo cars or does it need to be from a gsx or gst